Effect of turning upon the sub‐embryonic fluid and albumen of the egg of the Japanese quail

1. The effects of egg turning upon the formation of sub‐embryonic fluid (SEF), and albumen weight and composition are described up to day 8 of incubation.

2. The density of albumen increased, and the density of yolk sac contents decreased, during the first 5 d of incubation. Failure to turn eggs diminished these changes.

3. The rate of formation of SEF and its maximum weight were lower if eggs were not turned, as was the rate of decrease in albumen weight.

4. The concentration of sodium and chloride, as well as osmolality, were higher in SEF than in thin albumen, and were affected by a failure to turn eggs.

5. Static incubation altered the concentrations of yolk nutrients in SEF.

6. It is concluded that the formation of SEF is primarily dependent upon the transfer of sodium and chloride from albumen to SEF so creating an osmotic force for water movement in the same direction. Turning the eggs promotes this process by ensuring an adequate supply of ions in thin albumen adjacent to the blastoderm.     

Lithium induction of premature ovi‐position by the Japanese quail 1

1. The intramuscular injection of LiCl into laying Japanese quail 6 or 12 h subsequent to an oviposition induced early oviposition of the next egg.

2. The shells of eggs from Li‐treated birds were without speckling and weighed half or less as much as shells from Na‐treated birds. Many eggs were also deficient in albumen.     

Vitamin C supplementation and fear‐reduction in Japanese quail: Short‐term cumulative effects

1. Fear‐related behaviour was measured in individually‐housed Japanese quail which had received either untreated drinking water (UDW) or a vitamin C solution (ascorbyl‐2‐polyphosphate, APP, 1 g L‐ascorbic acid/1) for 1 or 4 d. Behavioural tests were carried out at 24 or 27 d of age. Water consumption was measured daily and plasma ascorbic acid (AA) content was assayed after differential treatment for 1 or 4 d.

2. The quail in the APP treatment groups drank significantly more than did those receiving untreated drinking water.

3. Supplementation with APP raised plasma AA concentrations substantially above those found in UDW quail. The lower AA concentrations found after APP treatment for 4 d rather than one may have reflected either inter‐assay variation or limited intestinal absorption following excess ingestion.

4. Quail treated with APP showed less home‐cage avoidance of a novel object and shorter tonic immobility fear reactions than did the UDW birds. The UDW quail showed remarkably similar avoidance and TI scores on test days 1 and 4. Conversely, continued treatment with APP further reduced avoidance scores but, although TI durations fell slightly with continued treatment there were no significant day effects.

5. It was concluded that APP supplementation can reduce underlying fearfulness but that it may not be necessary to continue treatment for longer than 24 h immediately prior to a known frightening event.     

Role of dietary γ‐linolenic acid in liver lipid metabolism in Japanese quail

1. The importance of linoleic acid (18:2n‐6) itself and of dietary y‐linolenic acid (18:3n‐6) as essential fatty acids (EFA) in Japanese quail were investigated with regard to liver lipid metabolism. Experimental diets were made by adding of 0, 2 or 4 g γ‐linolenic acid/kg, or 20 g linoleic acid/kg to an n‐6 EFA‐free diet. From 3 to 6 weeks of age, birds were fed equal amounts of experimental diets.

2. liver weight and lipid content in birds fed the 2 and 4 g γ‐linolenic acid/kg diet were significantly lower than those in birds fed the γ‐linolenic acid‐free diet. However, no significant difference was observed between the γ‐linolenic acid‐ and linoleic acid‐supplemented diets.

3. In birds fed the 4 g γ‐linolenic acid/kg diet, the proportion of arachidonic acid in the liver lipid was similar to that in quail fed the 20 g linoleic acid/kg diet, implying a conversion rate from linoleic acid to y‐linolenic acid of approximately 20% of whole body content.

4. It is concluded that linoleic acid itself is not essential for Japanese quail and that at least 2 g/kg of γ‐linolenic acid in the diet completely prevents liver enlargement accompanied by lipid accumulation.     

The role of histamine and fish meal in the incidence of gizzard erosion and pro‐ventricular abnormalities in the fowl

1. The role of certain fish meals in the production of localised gizzard erosion is confirmed.

2. Lesions typical of gizzard erosion could be produced by the addition of histamine to the diet.

3. The amount of histamine occurring naturally in fish meal depends on the species of fish and the extent and nature of bacterial spoilage.

4. These variables may explain why histamine has not been implicated previously and also why there have not been consistent associations between the condition and geographical source or common factors in bulk consignments of the meal.     

The replacement of some of the soybean meal by the first‐limiting amino acids in practical broiler diets

1. Four trials were carried out with broilers from 5 to 9 weeks of age in order to determine the effect of reducing dietary protein concentration, with and without special supplementations of methionine and lysine, on the amount of carcass fat.

2. In all trials fat deposition increased progressively as the protein concentrations of well‐balanced standard finisher diets were lowered by replacing soybean meal with sorghum grains (milo).

3. The increased degree of fatness was the result of graded increases in food consumption, and consequent decreases in food utilisation, caused by inadequate dietary protein.

4. In three out of four trials the above negative trends could be partly or completely reversed by special supplementations with methionine and lysine in amounts to restore the dietary concentration of these first‐limiting amino acids to those of the control diets.

5. It appears that broilers overeat in a compensatory attempt to obtain the limiting amino acids required for optimal growth rate, as long as the deficiency is not severe enough to cause an amino acid imbalance.     

Responses in growth,food intake and food conversion efficiency to different dietary protein concentrations in meat‐type lines of Japanese quail

1. A total of 360 Japanese quail of 4 commercial meat‐type lines and two diet treatments (260 and 216 g/kg or 238 and 195 g/kg of crude protein (CP) in the starter and grower diet, respectively) were used.

2. The positive effect of a high CP diet on body weight was significant only for the first 4 weeks after hatching.

3. The mean age at inflection point of the growth curve (t ⁺) across lines and sexes was 1.4 d (0.6 to 2.8 d within line/sex groups) earlier for quail fed on a high CP diet than in quail receiving a low CP diet. The inflection (y ⁺) and asymptotic (A) weights were similar under both dietary protein concentrations. Nevertheless, the shape of the growth curve, characterised by the ratio y⁺1A and parameter of the maturing rate k, was significantly influenced by diet.

4. A higher food intake and less efficient food conversion were found for quail fed on a high CP diet in the period from 15 to 28 d of age.

5. The fattening traits such as body weight, cumulative food intake and food conversion, were not affected by dietary CP content at the age of 5 weeks.

6. The effects of line on body weight, food intake and food conversion are discussed.     

Threat‐induced behavioural inhibition in Japanese quail genetically selected for contrasting adrenocortical response to mechanical restraint

1. Behavioural and adrenocortical responses to brief mechanical restraint were examined in 28‐d‐old female Japanese quail of two lines which had been genetically selected over several generations for either reduced (LS, low stress) or exaggerated (HS, high stress) plasma corticosterone response to brief immobilisation in a metal box.

2. As expected, quail of the LS line showed lower adrenocortical responses to restraint than did their HS line counterparts. The LS quail also struggled much sooner and more often during the 5 min restraint period than did the HS ones. Collectively, these and previously reported line differences in behavioural, cate‐cholamine and adrenocortical responsiveness are consistent with an interpretation based on the adoption of active and passive coping strategies respectively by LS and HS quail upon their exposure to alarming stimuli.     

The quality of herbage ingested by cattle in rotationally grazed semi‐arid grassveld of the eastern Cape

Oesophageal fistulated steers were used to sample herbage daily during periods of occupation on veld in good and moderate condition. Forage quality was assessed in terms of in vitro dry matter digestibility and digestible crude protein. The quality of herbage ingested remained fairly constant as forage availability declined during periods of occupation, even when swards were grazed very severely. Digestibility declined somewhat from spring through to winter, but digestible crude protein content in the diet was unaffected by time of year. The quality of forage ingested during winter was nevertheless still high, even after a full growing season's rest. It was sufficient for growing steers to gain 0,75 kg livemass per day. Trends were similar on both veld condition types. It was concluded that, in semi‐arid grassveld of the eastern Cape, forage availability is likely to have a greater influence on animal performance than forage quality.     

The effectiveness of in‐plant chlorination in poultry processing

1. Sampling carcasses after plucking or after the post‐evisceration spray‐wash showed that 10 or 20 ppm available chlorine in the processing‐plant water supply caused little reduction in carcass contamination.

2. When 20 ppm chlorine was used in the water supply to parts of the processing‐plant other than the mechanical immersion chilling system, counts of faecal and spoilage bacteria from carcasses were reduced approximately 10‐fold after passage through the chilling system; bacterial numbers were correspondingly decreased in the chiller water due to a carry‐over of chlorine from the final spray‐washer.

3. Artificial contamination of carcasses with a readily identifiable strain of Escherichia coli confirmed the occurrence of cross‐contamination during plucking and evisceration; in‐plant chlorination reduced neither the proportion of carcasses contaminated nor the numbers of organisms transferred at these stages.

4. In most cases the chlorine‐resistance of poultry spoilage pseudo‐monads was greater than that of E. coli; hence in‐plant chlorination is to be recommended for processing‐plant water supplies which carry such spoilage organisms.     

The microstructure of the cuticle‐less shell of the eggs of the domestic hen

1. Open pores were a notable feature of the shell of hens' eggs which were naturally devoid of cuticle.

2. In contrast with normal eggs, the surface of the cuticle‐less shell was irregularly contoured and, in many instances, deeply fissured.     

The use of n‐paraffin‐grown yeast as the main source of protein in diets for chicks

1. n‐Paraffin‐grown yeast and a mixture of soyabean meal and fish meal were compared in the net protein utilisation (NPU) test, and as protein supplements in diets for broilers up to 4 weeks of age.

2. The difference between the NPU values, 0.66 for yeast and 0.80 for the soyabean meal and fish meal mixture, could largely be attributed to the high nucleic acid content of the yeast.

3. Chicks given the diet containing yeast (190 g/kg) did not grow as rapidly as those given the soyabean meal and fish meal reference diet, and the reduced growth could only partly be explained by a marginal deficiency of methionine.

4. Food conversion efficiency with the yeast diet was improved by maize oil while responses to α‐tocopheryl acetate and sodium selenite were inconsistent.

5. Chicks grew well when yeast replaced fish meal in the mixture of soyabean meal and fish meal, and when fish meal (194 g/kg diet) was the sole protein supplement.     

Transport of L‐valine by the chicken caecum

1. We have studied L‐valine transport by the caecal segments of 6‐ to 8‐week‐old chickens. Isolated enterocytes from the proximal caecum incubated with 0.1 mM L‐valine can accumulate the substrate against a concentration gradient. After 50 min incubation, the intracellular L‐valine concentration reached 0.53 mM, a value higher than that observed in enterocytes from the jejunum (0.34 mM; P< 0.01).

2. Enterocytes from the medial and distal caecal regions are unable to transport L‐valine uphill (cell concentration: 0.1 mM).

3. Amino acid accumulation by proximal caecal cells was Na⁺‐dependent and was inhibited by ouabain and 2,4‐dinitrophenol. L‐methionine inhibits L‐valine uptake and a 2.5 mM concentration abolishes the capacity of enterocytes to accumulate the substrate.

4. The high accumulation ratios shown by the proximal caecum for L‐valine suggest a role for this intestinal segment in the absorption of neutral amino acids present in the caecal chamber.     

Responses of the reproductive vascular system during the egg‐formation cycle of unanaesthetised laying hens

1. Vascular adjustments to the process of egg formation were examined in the unanaesthetised laying hen, by the radioactive microspheres method.

2. Three‐ to four‐fold increases in blood flow were found in segments surrounding the egg during its passage along the oviduct, possibly due to an enhanced metabolic activity in the muscle layer of the oviduct.

3. Shell‐gland blood flow was minimal in the absence of an egg and increased gradually to a maximum (5‐fold) about 5 h after entrance of the egg into the shell gland. This parallels the rate of calcification of the egg shell.

4. Changes in blood flow in the ovarian follicles and other parts of the oviduct were small while the egg was in the shell gland. This might be typical for the reproductive system of the fowl, which undergoes little structural alteration during egg formation.     

The incidence of breast‐blister down‐grading in broiler chickens

1. A survey was conducted into down‐grading due to breast blisters at a large processing plant.

2. The relationships between incidence of down‐grading and age, body weight, sex, size of rearing site and its distance from the processing plant, and various weather conditions during the rearing period of each flock were examined using regression analysis.

3. Age and body weight and rearing site size were the only factors significantly correlated with amount of blistering.     

The role of Bcl-xL and nuclear factor-��B in the effect of taxol on the viability of dendritic cells

Taxol has been used effectively in cancer therapies. Our previous study demonstrated that taxol induced altered maturation and improved viability of dendritic cells (DCs). However, the effects of taxol on DC viability have not been fully elucidated. In the present study, flow cytometric analyses revealed that taxol treatment significantly increased the number of viable DCs and the expression levels of a representative anti-apoptotic protein Bcl-xL. Furthermore, mobilization of the p65 subunit of nuclear factor-κB (NF-κB) from the cytosol to the nucleus in DCs was observed by confocal microscopy. An inhibition assay using N-p-tosyl-_L-phenylalanine chloromethyl ketone confirmed that NF-κB was intimately involved in the effects of taxol on DC viability. In addition, we investigated the mechanisms of taxol enhancement of DC viability. Since taxol is a popular anticancer agent used in clinic, this study may provide a rationale for the use of taxol in DC immunotherapy to treat cancer patients. Taken together, these results confirm that taxol increases DC viability, and this information may provide new insights for new clinical applications of both taxol and DCs.